Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C27/00—Rotorcraft; Rotors peculiar thereto
  • B64C27/32—Rotors
  • B64C27/46—Blades
  • B64C27/473—Constructional features
  • B64C27/50—Blades foldable to facilitate stowage of aircraft
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
  • B64C11/16—Blades
  • B64C11/20—Constructional features
  • B64C11/28—Collapsible or foldable blades
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
  • B64C11/02—Hub construction
  • B64C11/04—Blade mountings
  • B64C11/06—Blade mountings for variable-pitch blades
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
  • B64U30/00—Means for producing lift; Empennages; Arrangements thereof
  • B64U30/20—Rotors; Rotor supports
  • B64U30/29—Constructional aspects of rotors or rotor supports; Arrangements thereof
  • B64U30/293—Foldable or collapsible rotors or rotor supports
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
  • B64U50/00—Propulsion; Power supply
  • B64U50/10—Propulsion
  • B64U50/13—Propulsion using external fans or propellers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
  • B64C11/30—Blade pitch-changing mechanisms
  • B64C11/32—Blade pitch-changing mechanisms mechanical

Definitions

• the invention relates to the field of aircraft engine propellers, in particular propellers controlled in rotation at a substantially constant speed.
• the subject of the invention is a propeller for an aircraft engine intended to be rotated about an axis of propeller rotation, the propeller comprising a hub and a plurality of blades distributed circumferentially around the hub. and further comprising:
• control means in incidence of the blades configured to rotate said blade support relative to the hub, according to said incidence timing axis;
• a blade folding / unfolding control member configured to pivot said blade root relative to the blade support according to said folding axis, said folding / unfolding control member comprising a first element and a second element movable in translation relative to each other, the first element being mounted on said hub with a first pivot connection and the second element being mounted on a transmission device to the first using a second pivot connection, the transmission device being connected to said blade root;
• a passive device for synchronizing the folding / unfolding of the blades comprising a central synchronization element rotatably mounted relative to the hub according to said axis of propeller rotation, and a coupling element associated with each blade, said coupling element comprising a first end mounted on said blade root according to a first ball joint connection, and a second end mounted on said central synchronization element by means of a second ball joint.
• the invention is remarkable in that it makes it possible to respond to the need identified above in a clever, simple and efficient manner.
• the implementation of the pivot / ball joints makes it possible to introduce degrees of freedom of movement that are useful for supporting the pivoting of the blades when they are wedged. in incidence.
• these pivot / ball joints are useful for the kinematics of folding / unfolding of the blades, a movement during which the central synchronizing element rotates freely around the hub along the axis of rotation of the helix.
• the passive synchronization device not only makes it possible to avoid the occurrence of imbalances during the folding / unfolding movements, but also makes it possible to provide a number of folding / unfolding control members that are smaller than number of blades of the propeller.
• the invention is also remarkable in that it has a design that can be implemented on existing propellers variable pitch of the blades, without causing significant changes.
• the invention furthermore exhibits at least one of the following optional features, singly or in combination.
• the propeller comprises at least two blades folding / unfolding control members, respectively associated with two blades.
• the number of these control members may be less than the number of blades, but may be alternately identical to the latter.
• the number of control members is half that of the blades of the propeller.
• a single folding / unfolding control member could be associated with all the blades of the propeller.
• said blade folding / unfolding control member is a controlled cylinder, preferably a hydraulic cylinder.
• the cylinder can be controlled in "pusher” or “puller” modes, depending on the design of the propeller.
• the jack in “puller” mode, can fulfill the function of damper.
• each connecting element is a connecting rod.
• said central synchronization element is a ring.
• said transmission device comprises two links articulated one on the other.
• the blade folding axis and the incidence pinning axis are substantially orthogonal.
• the number of blades is between one and four, even if a greater number could be provided, without departing from the scope of the invention.
• the folding / unfolding control member is oriented substantially parallel to the axis of propeller rotation when the blades are in an extended active position.
• the invention also relates to an aircraft engine comprising a helix as described above, preferably configured so that the propeller rotates at a substantially constant speed along its axis of rotation. Nevertheless, it is conventionally indicated that the rotational speed of the propeller can be controlled at a slightly lower speed by the pilot, for purposes of thrust optimization or fuel consumption, depending on the mission.
• FIG. 1 shows a schematic perspective view of a helix according to the invention, in an active position deployed;
• Figure lb is a schematic side view of the propeller shown in Figure la;
• Figure 2a is a view similar to that of Figure la, with the propeller shown in a position close to the retracted position;
• - Figure 2b is a view similar to that of Figure lb, with the propeller shown in a position close to the retracted position; and - Figure 3 is a partial perspective view of the propeller shown in Figure la, and shown in more detail.
• a propeller 2 for an aircraft engine 1 for example a drone engine. It is preferably a motor adapted for a vehicle with a mass of the order of five tons, and whose propeller 2 is intended to be rotated at a substantially constant speed along its axis of rotation. propeller 4, for example at a maximum speed of the order of 2000 rev / min.
• the engine 1 is conventionally equipped with a control system (not shown), making it possible to order a variation in the incidence of the blades of the propeller in order to maintain its constant speed of rotation, whatever the power requirements.
• the propeller 2 comprises a plurality of blades 6, here present four in number regularly distributed circumferentially around the axis of rotation 4. These blades 6 are carried externally by a propeller hub 8, rotatably mounted according to the invention. axis 4 relative to a fixed part of the engine.
• the invention has the particularity of offering a design allowing not only the wedging in incidence of its blades 6, but also the pounding / unfolding of its blades between an active deployed position as shown in Figures la and lb, and a position withdrawal or folded position, close to that shown in Figures 2a and 2b.
• the propeller 2 comprises a blade support 10 associated with each blade.
• This support 10 is arranged radially in relation to the axis of rotation 4, and passes through an opening 12 of the hub 8.
• the blade support 10 is pivotally mounted in this opening 12 of the hub, according to an axis of incidence timing 14 which is substantially oriented radially.
• each blade support 10 cooperates in known manner with means 16 for controlling the blades, housed inside the hub 8.
• These means 16 are configured to rotate simultaneously each blade support 10 in its opening 12, according to its axis of incidence timing 14. This pivoting is performed in response to an order of the engine control system, to change the pitch angle of the blades 6 of the propeller.
• each blade 6 comprises an aerodynamic portion and a base forming a blade root 6a.
• This connection defines a blade pusher axis 22, substantially tangential orientation relative to the axis of rotation 4 , thus being substantially orthogonal to the latter. Therefore, the pivotal connection 20 allows a pivoting of the blade 6 relative to its blade support 10, according to the blade bending axis 22 also substantially orthogonal to the bearing pinning axis 14.
• the folding of the blades is here provided for them to swing forward, since the engine has a traction configuration (called “puller”) in which the propeller is mounted at the front of the gas generator. Nevertheless, an inverted configuration (called “pusher”) could be adopted without departing from the scope of the invention. In this case, the blades are designed to bend backwards.
• At least one blade folding / unfolding control member 24 associated with a blade 6.
• a blade 6 For example, only two of the four blades 6 are equipped with such a blade member. 24 command, even if the number of these bodies could be lower or higher, without departing from the scope of the invention.
• the blade folding / unfolding control member 24 is configured to pivot the blade root 6a relative to the blade support 10, along the axis of folding 22. It is preferably a hydraulic cylinder controlled, comprising a cylinder body 28 and a cylinder rod 30 movable in translation relative to each other. In the deployed active position as shown in Figures la and lb, the control member 24 is oriented substantially parallel to the axis of rotation 4 of the helix.
• the cylinder body 28 is mounted on a rear part of the hub 8 by means of a first pivot link 32a, while the cylinder rod 30 is mounted on a transmission device 36 by means of a second link. pivot 32b.
• the transmission device 36 comprises two links 37 articulated one on the other, and whose one is also articulated on the blade root 6a, and the other is articulated on a fitting 38 integral in rotation with the blade support 10.
• the three axes of articulation are here parallel to each other, and also parallel to the blade folding axis 22.
• the two links 37 follow one another in the radial direction, being arranged externally to the hub 8.
• the link located radially inwardly has an eyelet (referenced 50 in FIG. 3) for connection to the jack rod 30, at the level of which the second pivot link 32b is made.
• the axes supporting the first and second pivot links 32a, 32b are preferably parallel to the blade bending axis 22.
• the propeller 2 comprises a passive device 40 for synchronizing folding / unfolding of the blades 6.
• This device 40 firstly comprising a central synchronization element 42 in the form of a ring, arranged around the front part of the hub 8
• This ring 42 is locked in translation along the axis of rotation of the helix 4, and is only rotatable along the same axis 4 relative to the hub 8.
• It also comprises a coupling element 44 associated with each blade 6, preferably rod-shaped. Its first end is mounted on the blade root 6a according to a first ball joint 32c, and its second end is mounted on the central synchronization ring 42 by means of a second ball joint 32d.
• Each connecting rod 44 extends substantially forward, and has an angle in the radial direction when viewed in front view.
• the axes supporting the first and second ball joints 32c, 32d are preferably orthogonal to each other. Indeed, the axis supporting the first ball joint 32c, whose orientation is symbolized by the dotted line 52, is parallel to the blade bending axis 22, while the axis supporting the second ball joint 32d, of which the orientation is symbolized by the dotted line 54, is parallel to the axis of rotation 4 of the helix.
• each blade support 10 pivots about its axis 14 relative to the hub 8. This pivoting is accompanied by a displacement of the cylinders 24 and connecting rods 44, thanks to the pivot links / ball joints 32a-32d.
• the rods 44 it may be accompanied by a small rotation of the ring 42 around the hub 8, along the axis 4.
• the control members 24 When a folding of the propeller is controlled, the control members 24 are actuated accordingly until the blades 6 reach their withdrawal position close to that shown in Figures 2a and 2b.
• the cylinder rod 30 leads the radially inner link to pivot forward, taking with it the other link which in turn pushes the blade foot 6 to pivot forwardly along the axis 22.
• the two links 37 and pass from a configuration where they are substantially aligned radially to a configuration in which they form a V open rearward.
• the retained design can be such that in the unfolded position, the two links 37 can adopt a position in which they are slightly inclined with respect to each other, so as to form a very flared V and especially in the opposite direction to the aforementioned V, open towards the rear. This prevents the accidental return of the blades in the folded position.
• the pivoting of the blades 6 is performed at an angle close to 90 °, so that their initially radial orientation gradually tilts to become substantially axial.
• the first end of each connecting rod 44 is driven forward, while this displacement is compensated by the rotation of the ring 42 around the hub 8, caused by the induced displacement of the second end of each connecting rod 44.
• the folding of the propeller 2 is advantageously performed in a synchronized manner.
• the folding of the propeller 2 forward must oppose the aerodynamic force applying to the blades 6 in flight, the propeller turns or it is stopped.
• the principles described above are realized in the opposite direction.
• the unfolding / deployment can be performed while the propeller rotates, or with the propeller stopped.
• the centrifugal force advantageously helps the deployment.

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• Engineering & Computer Science (AREA)
• Aviation & Aerospace Engineering (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transmission Devices (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Toys (AREA)

Priority Applications (4)

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Publications (1)

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ID=56611324

Family Applications (1)

Country Status (6)

Cited By (1)

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Citations (4)

Family Cites Families (28)

• 2016
  • 2016-03-21 FR FR1652398A patent/FR3048953B1/fr not_active Expired - Fee Related
• 2017
  • 2017-03-20 CN CN201780017854.2A patent/CN108778926B/zh active Active
  • 2017-03-20 US US16/086,817 patent/US10683081B2/en active Active
  • 2017-03-20 JP JP2018549216A patent/JP6921848B2/ja active Active
  • 2017-03-20 WO PCT/EP2017/056512 patent/WO2017162561A1/fr not_active Ceased
  • 2017-03-20 EP EP17711221.6A patent/EP3433169B1/de active Active

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